Creating Tiramisu Sandwich Cookies is straightforward if you follow these simple steps:

1. Preheat Oven: Preheat your oven to 350°F (175°C). Line two baking sheets with parchment paper.
2. Mix Dry Ingredients: In a bowl, whisk together flour, cocoa powder, baking powder, baking soda, and salt. Set aside.
3. Cream Butter and Sugar: In a large mixing bowl, beat the softened butter and granulated sugar until light and fluffy.
4. Add Egg and Extracts: Add the egg, vanilla extract, and cooled coffee to the butter mixture. Mix until well combined.
5. Combine Mixtures: Gradually add the dry ingredients to the wet ingredients, mixing until just combined.
6. Scoop Dough: Use a cookie scoop to drop rounded tablespoons of dough onto the prepared baking sheets, spacing them about 2 inches apart.
7. Bake: Bake in the preheated oven for 15-20 minutes, or until the edges are set and the tops are slightly cracked.
8. Cool: Remove from the oven and allow the cookies to cool on the baking sheets for 5 minutes before transferring them to wire racks to cool completely.
9. Prepare Filling: In a separate bowl, combine mascarpone cheese, powdered sugar, heavy cream, and coffee liqueur (if using). Beat until smooth and creamy.
10. Assemble Cookies: Once the cookies are completely cool, spread a generous amount of the mascarpone filling on the flat side of one cookie. Top with another cookie, pressing gently to create a sandwich.
11. Dust with Cocoa: Lightly dust the assembled cookies with cocoa powder for a finishing touch.

These simple steps will guide you in creating these incredible cookies effortlessly!